Tan Zuoren, who had collected sensitive information about a major 2008 earthquake, lost his appeal against a five-year jail sentence on Wednesday. He and other activists in China have faced tougher controls in recent years.

Vincent Yu/AP

Protesters raise a picture of Chinese activist Tan Zuoren during a protest outside the Chinese government's liaison office in Hong Kong Wednesday. Mr. Tan, who had collected sensitive information about a major 2008 earthquake, earned five years in jail.

In China, “state power” is a nebulous concept, but a central one. And on Wednesday we got a reminder of just how easy it is – in the government’s eyes – to undermine it.

All Tan Zuoren did was to organize an online campaign to try to draw up a list of the children who died when schools collapsed in the 2008 Sichuan earthquake.

That was enough to earn the activist five years in jail for “inciting subversion of state power.” On Wednesday, a Sichuan provincial court upheld the sentence, which Mr. Tan had appealed in February.

Sometimes, “state power” in China seems massive, monolithic, and impregnable. The ruling Communist Party, to all intents and purposes, is the state; its rule is unquestionable, and it controls all three branches of government (and most of the fourth estate).

And then, sometimes, “state power” seems all too fragile, the men who wield it nervous that the slightest crack in the edifice will bring it tumbling down.

How else to explain why a list of children’s names could be subversive, except that the list – and its length – might make citizens wonder about the quality of school construction and the possibility that local officials did not do their jobs properly? And that such doubts would constitute a threat to the party’s legitimacy and thus to “state power”?

“The Chinese Constitution guarantees citizens’ rights to freedom of expression, but the government and its politicized judiciary appear to have again denied that right to an outspoken civil society activist,” says Phelim Kline, an Asia researcher with the New York based Human Rights Watch.

Civil society is all very well, the authorities appear to believe, so long as it acts within government guidelines. A government report finding that 5,335 children died in the earthquake was acceptable. Tan’s independent research, estimating a similar death toll, was not.

When Tan was sentenced, the judge said he was punishing him for an essay he had published abroad in 2007 about the 1989 crackdown in Tiananmen Square. Tan’s lawyers pointed out, though, that he was charged only in July 2009, after he had launched his list and angered local authorities by opposing a planned petrochemical plant.